This thesis describes the synthesis and characterization of triaminocyclopropenium, [C3(NR2)3]+, ionic liquids. A range of triaminocyclopropenium salts were prepared: D3h, C3h, C2v and Cs symmetric cations with a variety of substituents. D3h and C3h symmetric cations were prepared from pentachlorocyclopropane and dialkylamines, whereas a variety of methods were investigated for C2v and Cs symmetric cations, with the most versatile synthesis involving the alkylation of bis(dialkylamino)cyclopropenone followed by reaction with dialkylamine. Metathesis with a range of common ionic liquid anions was carried out to facilitate comparisons to other common classes of ionic liquids. The triaminocyclopropenium salts were characterized by standard techniques (1H-, 13C{1H}-NMR, ES+ MS, microanalysis) as well as particular physicochemical properties relevant to ionic liquids. The thermal behaviour was examined with DSC, with the majority of salts being liquid at room temperature. The viscosity of triaminocyclopropenium ionic liquids was similar to other classes of ionic liquid cations, in the range of 58.4 to 554 mPa s at 20 °C. This is despite the generally large size of the cations investigated, which also causes the conductivity to be lower. Triaminocyclopropenium ionic liquids show good ionicity, more than other common classes of ionic liquid cation, which is likely due to the relatively electron-rich nature of the cation. The thermal, electrochemical and chemical stability of triaminocyclopropenium ionic liquids was accessed. Good thermal stabilities were observed, with onset temperatures of 339 to 413 °C. The electrochemical window of [C3(NEt2)3]TFSA is 3.6 V, this is low due to the easy oxidation of the cation. The chemical stability is good under acidic, weakly-basic, weakly-nucleophilic, reducing and weakly-oxidising conditions, however, the cations are unstable to the strong nucleophile/base hydroxide. Triaminocyclopropenium ionic liquids showed a full range of solubility and miscibility: from fully miscible in water to fully miscible in hexane. A preliminary investigation of ionic liquid fluorides was carried out. While stable ionic liquids with naked fluorides were not obtained, ionic liquids with strongly-bound solvate molecules (ethanol and acetic acid) were seeen, and their viscosity, conductivity and density were measured. The attachment of hydroxyl functional groups to triaminocyclopropenium cations was seen to improve the stability of ionic liquid fluorides, although at the cost of high viscosity.

Ionic liquids are molten salts with melting points below 100 °C and they consist entirely of cations and anions. The development of ionic liquids, especially air and water stable types, has attracted extensive attention since they have outstanding physical properties. Part I of the study focused on the pre-electrolysis process performed to remove impurities from the ionic liquid, 1-butyl-1-methyl-pyrrolidinium bis(tri-fluoromethylsulfonyl)imide, ([BMP]Tf2N). Part II investigated the electroreduction of TaF5 and NbF5 from room temperature ionic liquid at 100 °C at a wide range of potentials and different time durations for the purpose of determining the optimal conditions for the electrodeposition of tantalum. The study was carried out using potentiostatic polarization for the pre-electrolysis treatments and electrodeposition and cyclic voltammetry to study the behaviour of the liquid at various stages. Potentiostatic depositions were complemented by scanning electron microscopy (SEM)/energy-dispersive x-ray analysis (EDX), x-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD) for characterization of the electrodeposits.

Ionic liquids are molten salts with melting points below 100 °C and they consist entirely of cations and anions. The development of ionic liquids, especially air and water stable types, has attracted extensive attention since they have outstanding physical properties. Part I of the study focused on the pre-electrolysis process performed to remove impurities from the ionic liquid, 1-butyl-1-methyl-pyrrolidinium bis(tri-fluoromethylsulfonyl)imide, ([BMP]Tf2N). Part II investigated the electroreduction of TaF5 and NbF5 from room temperature ionic liquid at 100 °C at a wide range of potentials and different time durations for the purpose of determining the optimal conditions for the electrodeposition of tantalum. The study was carried out using potentiostatic polarization for the pre-electrolysis treatments and electrodeposition and cyclic voltammetry to study the behaviour of the liquid at various stages. Potentiostatic depositions were complemented by scanning electron microscopy (SEM)/energy-dispersive x-ray analysis (EDX), x-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD) for characterization of the electrodeposits.

No description available.

Opioid abuse and in particular fentanyl, a synthetic opioid, has been of concern in the last decade. Fentanyl is an illicit drug of concern to due to its prevalence and potency. Research to date has focused on supporting law enforcement by developing methods suitable for chemical profiling and identifying fentanyl from various matrices. However, methods geared towards analysis of fentanyl isomeric analogues are rare. Analysis of isomers is challenging due to similar mass spectral fragmentation patterns and exhibiting co-elution using common gas chromatographic columns. Developing methods to use in forensic labs utilizing already available equipment will advance current capabilities in the detection of fentanyl compounds. Thus, investigation into alternative stationary phases and development of special gas-liquid chromatographic (GLC) based methods for isomeric fentanyl analogues has been done. Several studies were done to investigate the use of ionic liquid chromatographic phases in analyzing fentanyl analogues. The first study focused on investigating the thermal stability of ionic liquids to identify those suitable to withstand the high oven temperatures that was needed to elute fentanyl analogues in gas chromatography. Total synchronous fluorescence spectroscopy and differential scanning calorimetry were demonstrated to be sensitive enough to detect the decomposition products of ionic liquids. In the second study, gas chromatographic analysis was done on fentanyl analogues using an ionic liquid stationary phase as well as two commonly used stationary phases for comparison purposes. The applicability of the developed methods was tested using standard fentanyl analogue samples as well as in-house synthesized samples on all three columns. In the third study, quantitative structure property relationship equations were developed to predict the retention time of fentanyl analogues on two of the gas chromatographic stationary phases used in the second study.

Predictive methods have been employed to characterize chemical separation mediums including solvents and absorbents. These studies included creating Abraham solvation parameter models for room-temperature ionic liquids (RTILs) utilizing novel ion-specific and group contribution methodologies, polydimethyl siloxane (PDMS) utilizing standard methodology, and the micelles cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfate (SDS) utilizing a combined experimental setup methodology with indicator variables. These predictive models allows for the characterization of both standard and new chemicals for use in chemical separations including gas chromatography (GC), solid phase microextraction (SPME), and micellar electrokinetic chromatography (MEKC). Gas-to-RTIL and water-to-RTIL predictive models were created with a standard deviation of 0.112 and 0.139 log units, respectively, for the ion-specific model and with a standard deviation of 0.155 and 0.177 log units, respectively, for the group contribution fragment method. Enthalpy of solvation for solutes dissolved into ionic liquids predictive models were created with ion-specific coefficients to within standard deviations of 1.7 kJ/mol. These models allow for the characterization of studied ionic liquids as well as prediction of solute-solvent properties of previously unstudied ionic liquids. Predictive models were created for the logarithm of solute's gas-to-fiber sorption and water-to-fiber sorption coefficient for polydimethyl siloxane for wet and dry conditions. These models were created to standard deviations of 0.198 and 0.122 logunits for gas-to-PDMS wet and dry, respectively, as well as 0.164 and 0.134 log units for water-to-PDMS wet and dry, respectively. These models are particularly useful in solid phase microextraction separations. Micelles were studied to create predictive models of the measured micelle-water partition coefficient as well as models of measured MEKC chromatographic retention factors for CTAB and SDS. The resultant predictive models were created with standard deviations of 0.190 log units for the logarithm of the mole fraction concentration of water-to-CTAB, 0.171 log units for the combined logarithms of both the mole fraction concentration of water-to-CTAB and measured MEKC chromatographic retention factors for CTAB, and 0.153 log units for the combined logarithms of both the mole fraction concentration of water-to-SDS and measured MEKC chromatographic retention factors for SDS.

No description available.

New phosphonium and ammonium ionic liquids were prepared for use in two green applications. Ionic liquids are generating considerable current interest as media for electrochemical processes such as electrodeposition, which can be used to create thin films of a variety of compounds. For the first time, silicon deposition has been achieved in the phosphonium ionic liquid triethyl(2-methoxyethyl)phosphonium bis(trifluoromethylsulfonyl)amide (P201-TFSI). Subsequently, silicon has been deposited from a wide variety of precursors in order to optimize the thickness and morphology of the deposited films. The silicon films electrodeposited in the phosphonium ionic liquid show marked differences from those deposited in organic solvents, imidizolium and pyrrolidinium based ionic liquids. Phosphonium and ammonium ionic liquids were also investigated for use in carbon dioxide capture. Task-specific ionic liquids have shown great promise as agents for the physisorption and chemisorption of CO2 from combustion gas streams. Efforts to synthesize new task specific ionic liquids with multiple amine functionalities for CO2 capture are reported. Four different reaction pathways were explored for the synthesis of these materials. While this goal was not achieved in this work, task-specific phosphonium and ammonium ionic liquids offer the promise of opening up new areas in ionic liquid research. / text

Silver nanoparticles (sub 10 nm), supported on, or in, cellulose, have been demonstrated to be well stabilised and immobilised during application in a model continuous reaction: the reduction of 4-nitrophenol (4-NP) to 4-aminophenol with sodium borohydride. The production of these silver nanoparticles (NP), within the cellulose supports, was carried out by either in situ reduction of silver precursors absorbed into the preformed cellulose supports, or, by inclusion of ex situ synthesised NPs (prepared in DMSO solutions) in the dissolution of cellulose and trapping upon subsequent coagulation of cellulose. The effects of NP synthesis method (affecting particle size and agglomeration) and the cellulose morphology and porous structure were examined with respect to the catalytic activity of the materials. The in situ reduction of a silver salt with aqueous NaBH4 solutions (0.03 to 1.0 wt. %) led to tuneable Ag NP sizes with mean diameters of 5 to 11 nm (TEM) and metal loadings of 0.5-1.0 wt. %. The catalytic activity of these samples in the 4-NP reduction reaction (0.05 mM, 0.167 M NaBH4, 30 °C) was demonstrated to increase upon decreasing NP size: TOF values of 22–356 h-1, consistent with a Langmuir-Hinshelwood mechanism. The porous structure of these Ag-cellulose materials (0.2 to 294 m2 g-1) was demonstrated to be variable and dependent on drying treatments of the regenerated cellulose hydrogel. Thermal drying, freeze-drying and critical point drying resulted in materials with different bulk structure and porosity. In turn the different porosities resulted in extremely different catalyst activities, e.g. Ag-cellulose catalyst (0.3 mm disks) thin film, hydrogel and cryogel phases exhibited TOF values of 2, 12 and 178 h-1, respectively. In addition, the NP synthesis could be carried out in either the cellulose hydrogel or cryogel, which led to different extents of Ag NP catalyst stabilisation against agglomeration during the 4-NP reaction and catalyst recovery and recycling. The Ag NPs synthesised in the cryogel cellulose disks were observed to undergo agglomeration (TEM) after use in 4 repeat batch reductions, whilst those NPs synthesised in the hydrogel cellulose, prior to freeze-drying to the final cryogel catalyst material, did not exhibit any agglomeration upon 4 repeat reduction reactions. The ex situ reduction of Ag and Au NPs was carried out by the reduction of AgOAc and Au(OAc)3 by DMSO and variation of the NP synthesis parameters, such as time (10 min – 1h) and temperature (50 – 80 °C), allowed for control of the NP sizes (3 to 6 nm Ag NPs and 4 to 11 nm Au NPs, TEM). It was demonstrated that the addition of the polysaccharide starch (0.42 wt. % in DMSO) allowed for consistent Ag NP size (ca. 4 nm) to be achieved throughout the 8 h synthesis, the starch acting as both the reducing and capping agent, maintaining the small sizes and narrow particle size distributions of the NPs upon aging (72 h). A kinetic model with a bimolecular nucleation step was developed to describe this reduction of the silver acetate by the starch/DMSO system. However, contact of the NPs with solutions of imidazolium ILs, 1-Ethyl-3-methylimidazolium acetate (EmimOAc) and 1-Butyl-3-methylimidazolium chloride (BmimCl) in DMSO, used in the dissolution of cellulose, led to the oxidation of the Ag(0) and Au(0) NPs. Thus, when these NP solutions were mixed in cellulose solutions regeneration by phase inversion with the aim of preparing cellulose/NP composites led to materials with negligible metal loadings (AAS). This oxidation, of the metal NPS, was partially overcome by stabilisation of the starch capped Ag NPs by pre-treatment with cellulose (1:1 mixture of α and MC cellulose). However, the activity of the resulting Ag-cellulose catalyst (0.5 wt. % AAS, 6.7 nm TEM) was much lower than the Ag-cellulose catalysts prepared by in situ reduction of silver in the cellulose hydrogel, despite the comparable NP sizes. This was presumed to be a result of encapsulation of the Ag NPs by the cellulose, leading to a decrease in the accessible surface of the NPs. Finally, the use of Ag NP / cellulose composites, prepared by in situ reduction of silver in cellulose hydrogel beads (0.19 wt. %, 6.4 nm), were demonstrated in the continuous reduction of 4-NP in a packed bed reactor (τ’ 100 g s dm-3). The activation energies of the reactions of 4-NP catalysed by the Ag-cellulose catalyst materials were determined (3.2 to 9.4 kJ mol-1) from Arrhenius plots, which demonstrated that above 20 °C the reaction was likely subject to diffusion limitations in the cellulose beads. The high degree of stabilisation of the Ag NPs against agglomeration imparted by the cellulose support was demonstrated: the rate of reaction was observed to be constant over 120 h, treating 45 L of 4-NP solution, with the catalyst material after use demonstrating no significant leaching of silver, or agglomeration, of NPs (AAS, TEM).

This research is focused on development of routes towards the rational design of nanoparticle catalysts. Primarily, it is focused on two main projects; (1) the use of imidazolium-based ionic liquids (ILs) as greener media for the design of quasi-homogeneous nanoparticle catalysts and (2) the rational design of heterogeneous-supported nanoparticle catalysts from structured nanoparticle precursors. Each project has different studies associated with the main objective of the design of nanoparticle catalysts.<p> In the first project, imidazolium-based ionic liquids have been used for the synthesis of nanoparticle catalysts. In particular, studies on recyclability, reuse, mode-of-stability, and long-term stability of these ionic-liquid supported nanoparticle catalysts have been done; all of which are important factors in determining the overall greenness of such synthetic routes. Three papers have been published/submitted for this project. In the first publication, highly stable polymer-stabilized Au, Pd and bimetallic Au-Pd nanoparticle catalysts have been synthesized in imidazolium-based 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6) ionic liquid (Journal of Molecular Catalysis A: Chemical, 2008, 286, 114). The resulting nanoparticles were found to be effective and selective quasi-homogeneous catalysts towards a wide-range of hydrogenation reactions and the catalyst solution was reused for further catalytic reactions with minimal loss in activity. The synthesis of very pure and clean ILs has allowed a platform to study the effects of impurities in the imidazolium ILs on nanoparticle stability. In a later study, a new mode of stabilization was postulated where the presence of low amounts of 1-methylimidazole has substantial effects on the resulting stability of Au and Pd-Au nanoparticles in these ILs (Chemical Communications, 2009, 812). In further continuation of this study, a comparative study involving four stabilization protocols for nanoparticle stabilization in BMIMPF6 IL is described, and have shown that nanoparticle stability and catalytic activity of nanoparticles is dependent on the overall stability of the nanoparticles towards aggregation (manuscript submitted).<p> The second major project is focused on synthesizing structurally well-defined supported catalysts by incorporating the nanoparticle precursors (both alloy and core shell) into oxide frameworks (TiO2 and Al2O3), and examining their structure-property relationships and catalytic activity. a full article has been published on this project (Journal of Physical Chemistry C, 2009, 113, 12719) in which a route to rationally design supported catalysts from structured nanoparticle precursors with precise control over size, composition, and internal structure of the nanoparticles has been shown. In a continuation of this methodology for the synthesis of heterogeneous catalysts, efforts were carried out to apply the same methodology in imidazolium-based ILs as a one-pot media for the synthesis of supported-nanoparticle heterogeneous catalysts via the trapping of pre-synthesized nanoparticles into porous inorganic oxide materials. Nanoparticle catalysts in highly porous titania supports were synthesized using this methodology (manuscript to be submitted).